Design of an imaging bolometer upgrade for JT-60U

Peterson, B. J.*; Konoshima, Shigeru; Kostryukov, A. Y.*; Kawashima, Hisato; Seo, D. C.*; Miroshnikov, I. V.*; Ashikawa, Naoko*; Parchamy, H.*; Liu, Y.*; JT-60 Team

Infrared Imaging Video Bolometers (IRVB) provide a reactor relevant alternative to conventional resistive bolometers due to the radiation durability of the used materials, the lack of wire feedthroughs and in vessel cabling and the lack of signal drift during steady state operation. An IRVB prototype has been successfully installed and operated on the JT-60U tokamak demonstrating its applicability to a reactor environment. In this paper we present the design of an upgraded version of this IRVB. The 2.5 micron gold foil will be replaced with a 5 micron tantalum foil for improved rigidity. Enlarged vacuum window and additional IR periscope with large IR lenses and mirrors will improve the optical throughput. An improvement in the sensitivity of the IRVB by at least a factor of 50 is expected.